diff --git a/boards/shields/rpi_pico_uno_flexypin/Kconfig.shield b/boards/shields/rpi_pico_uno_flexypin/Kconfig.shield
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+# Copyright (c) 2024 TOKITA Hiroshi
+# SPDX-License-Identifier: Apache-2.0
+
+config SHIELD_RPI_PICO_UNO_FLEXYPIN
+	def_bool $(shields_list_contains,rpi_pico_uno_flexypin)
diff --git a/boards/shields/rpi_pico_uno_flexypin/doc/img/rpi_pico_uno_flexypin.png b/boards/shields/rpi_pico_uno_flexypin/doc/img/rpi_pico_uno_flexypin.png
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diff --git a/boards/shields/rpi_pico_uno_flexypin/doc/index.rst b/boards/shields/rpi_pico_uno_flexypin/doc/index.rst
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+.. _rpi_pico_uno_flexypin:
+
+RaspberryPi Pico to UNO FlexyPin Adapter
+########################################
+
+Overview
+********
+
+Raspberry Pi Pico to Uno `FlexyPin Adapter` is a converter-PCB to Arduino UNO form-factor
+from Raspberry Pi Pico that is released in Open Source Hardware.
+This board design to use with `FlexyPin`.
+The FlexyPin holds Pico and contacts to castellated through-hole.
+With simple soldering, it can also be used as a board to convert the RapsberryPi Pico
+o the Arduino UNO form factor.
+
+.. image:: img/rpi_pico_uno_flexypin.png
+     :align: center
+     :alt: RaspberryPi Pico to UNO FlexyPin Adapter
+
+Pins Assignment of the RaspberryPi Pico to UNO FlexyPin Adapter
+===============================================================
+
++---------------------+------------+
+| Rpi-Pico Pin        | UNO Header |
++=====================+============+
+| GP0 (UART0 TX)      | D1         |
++---------------------+------------+
+| GP1 (UART0 RX)      | D0         |
++---------------------+------------+
+| GP2                 | D8         |
++---------------------+------------+
+| GP3                 | D9         |
++---------------------+------------+
+| GP4                 | D2         |
++---------------------+------------+
+| GP5                 | D3         |
++---------------------+------------+
+| GP6                 | D4         |
++---------------------+------------+
+| GP7                 | D5         |
++---------------------+------------+
+| GP8                 | D6         |
++---------------------+------------+
+| GP9                 | D7         |
++---------------------+------------+
+| GP13                | A3         |
++---------------------+------------+
+| GP14 (I2C1 SDA)     | A4         |
++---------------------+------------+
+| GP15 (I2C1 SCL)     | A5         |
++---------------------+------------+
+| GP16 (SPI0 RX/CIPO) | D12        |
++---------------------+------------+
+| GP17 (SPI0 CS)      | D10        |
++---------------------+------------+
+| GP18 (SPI0 SCK)     | D13        |
++---------------------+------------+
+| GP19 (SPI0 TX/COPI) | D11        |
++---------------------+------------+
+| GP20                | D14        |
++---------------------+------------+
+| GP21 (I2C0 SCL)     | D15        |
++---------------------+------------+
+| GP26 (I2C0 SDA)     | A0         |
++---------------------+------------+
+| GP27                | A1         |
++---------------------+------------+
+| GP28                | A2         |
++---------------------+------------+
+
+Programming
+***********
+
+Set ``-DSHIELD=rpi_pico_uno_flexypin`` when you invoke ``west build``.
+This shield is just a converter, so it is usually used with other Arduino shield.
+
+For example,
+
+.. zephyr-app-commands::
+   :zephyr-app:  samples/net/wifi
+   :board: rpi_pico
+   :shield: 'rpi_pico_uno_flexypin;esp_8266_arduino'
+   :goals: build
+
+References
+**********
+
+.. target-notes::
+
+.. _FlexyPin:
+   https://github.com/solderparty/flexypin
+
+.. _FlexyPin Adapters:
+   https://github.com/solderparty/flexypin_adapters_hw
diff --git a/boards/shields/rpi_pico_uno_flexypin/rpi_pico_uno_flexypin.overlay b/boards/shields/rpi_pico_uno_flexypin/rpi_pico_uno_flexypin.overlay
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index 00000000000..3ddf2872883
--- /dev/null
+++ b/boards/shields/rpi_pico_uno_flexypin/rpi_pico_uno_flexypin.overlay
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+/*
+ * Copyright (c) 2024 TOKITA Hiroshi
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	arduino_header: connector {
+		compatible = "arduino-header-r3";
+		#gpio-cells = <2>;
+		gpio-map-mask = <0xffffffff 0xffffffc0>;
+		gpio-map-pass-thru = <0 0x3f>;
+		gpio-map =
+			<0 0 &pico_header 26 0>,  /* A0 */
+			<1 0 &pico_header 27 0>,  /* A1 */
+			<2 0 &pico_header 28 0>,  /* A2 */
+			<3 0 &pico_header 13 0>,  /* A3 */
+			<4 0 &pico_header 14 0>,  /* A4 */
+			<5 0 &pico_header 15 0>,  /* A5 */
+			<6 0 &pico_header 1 0>,   /* D0 */
+			<7 0 &pico_header 0 0>,   /* D1 */
+			<8 0 &pico_header 4 0>,   /* D2 */
+			<9 0 &pico_header 5 0>,   /* D3 */
+			<10 0 &pico_header 6 0>,  /* D4 */
+			<11 0 &pico_header 7 0>,  /* D5 */
+			<12 0 &pico_header 8 0>,  /* D6 */
+			<13 0 &pico_header 9 0>,  /* D7 */
+			<14 0 &pico_header 2 0>,  /* D8 */
+			<15 0 &pico_header 3 0>,  /* D9 */
+			<16 0 &pico_header 17 0>, /* D10 */
+			<17 0 &pico_header 19 0>, /* D11 */
+			<18 0 &pico_header 16 0>, /* D12 */
+			<19 0 &pico_header 18 0>, /* D13 */
+			<20 0 &pico_header 20 0>, /* D14 */
+			<21 0 &pico_header 21 0>; /* D15 */
+	};
+};
+
+arduino_spi: &pico_spi {};
+arduino_i2c: &pico_i2c0 {};
+arduino_serial: &pico_serial {};